Cleanup toThrowError constructor lookup to work in older IE

- Also use the existing browser detection for phantom

spec/helpers/BrowserFlags.js

@@ -20,4 +20,8 @@
     return /Firefox\/([0-9]{0,})/.exec(userAgent);
   });
 
+  env.phantomVersion = browserVersion(function(userAgent) {
+    return /PhantomJs\/([0-9.]{0,})+/.exec(userAgent);
+  });
+
 })(jasmine.getEnv());